You can activate the yeast by busting that pouch (or Smack Pack), which releases the nutrients into the yeast and starts the fermentation process. The yeast culture, then will start its metabolism, which will lead to the production of CO2 and bloat or swell the package. Each and every Wyeast package contains a minimum of 100 billion yeast cells (Go ahead....we dare you to count them!) Pitching rates could vary depending on the conditions and the temperature. For lagers, Wyeast Laboratories recommend starting with warm temperatures for the inoculation process (68-70F or 20-21C). If the conditions are colder, a higher pitching rate is recommended which can be achieved with an additional activator or by creating a starting culture first.